Magneto-optical Kerr effect analysis of magnetic nanostructures

We present a treatment of polarized light analysis and noise sources relevant to magneto-optical Kerr effect (MOKE) measurements of magnetic nanostructures and give performance details of our state-of-the-art MOKE magnetometer in these terms. By considering the various signal contributions, we are able to determine experimental conditions for optimal MOKE signal dynamic range and signal-to-noise ratio. A description of our MOKE instrument includes a novel facility to locate magnetic nanostructures by producing a susceptibility map of the sample surface. The performance of the magnetometer is demonstrated by hysteresis loops of single 100-200 nm wide magnetic nanowires, including a loop obtained with no time averaging during a single magnetic field cycle.